1

Status of MRPC-TOF

Wang YiDepartment of Engineering PhysicsTsinghua University, Beijing, China

2

Outline• Conceptual design of TOF• Beam test results

– Layout– Preparation– Some Details on Setup

• • Conclusion

– Test Results– Comparison– Conclusion

• The MRPC is developed for the TOF of SoLID • Main Requirements for TOF:

– /k separation up to 2.5GeV/c – Time resolution < 80ps– Rate capability > 10kHz/cm²

• MRPC TOF wall we designed contain 150 MRPC modules in total, with 50 gas boxes and 3 counters in each box, covering the area of 10m².

1.Conceptual design of SOLID-TOF

3

MRPC1MRPC2MRPC3

100cm

16cm28cm

The MRPC module we tested is the prototype of smallest one.

Total channel ~3300

4

1.Introduction: MRPC module

• The prototype of high rate MRPC modules with low resistivity glass electrodes can work under the flux of 60kHz/cm² in previous test in HZDR and GSI.

• Low resistivity glass is black in color, and the volume resistivity can reach ~1010.cm. (For float glass, the volume resistivity is ~1012.cm)

Volume resistivity: ~1010.cm

5

The design of MRPC readout

1.Introduction: MRPC module

363mm

219mm171mm

Interval 3mm

Strip width 25mm

Readout mode Differential

DimensionsLength/mm Width/mm Thickness/mm

Gas gap - - 0.25×10

Inner glass 320 130-171 0.7

Outer glass 330 138-182 1.1

Mylar 335 153-198 0.18

Inner PCB 350 182-228 1.6

Outer PCB 350 172-218 0.8

Honeycomb 330 153-198 6

Outer glassInner glass

Mylar

Inner PCB

Outer PCB

Honeycomb

Gas Mixture(Pre-mixed) Freon 90%iso-butane 5%SF6 5%

Working Voltage ±6800V

Electrical field ~108.8kV/cm

6

TOF electronics

• Fast preamplifier： Maxim3760 (RICE Univ.) Ninos (TOT) (ALICE) Padi (TOT) (GSI) CAD (TOT)(Tsinghua) • QDC (CAEN, 25fC/bin)• TDC HPTDC (ALICE, 25ps/ch) GET4 (GSI, 25ps/ch) FPGA TDC (GSI and other)

• DAQ

77

Comparison of different FEE

CAD-1.0 PADI-1 NINO-25 NINO-13

Peaking time ~1ns <1ns 1ns 0.6ns

Linear range 1000mA*1 -60-60mA*1 0-100fC*2 0-100fC*2

Time jitter <20ps, rms*3 <15ps, rms*4 10-25ps, rms 6-25ps, rms

Power consumption 10mW/ch <30mW/ch 30mW/ch 5mW/ch

Input type S.E. DIFF. DIFF. DIFF.

Input impedance 50-70W 48-58W 30-100W 30-100W

Discriminator threshold 263mA*1 10-400mA*1 20-100fC*2 20-100fC*2

CMOS process 0.35mm 0.18mm 0.25mm 0.13mm

*1: for current pulse with 0.3ns rise time, 1-2ns FWHM, and 0.3ns fall time*2: for square current pulse with 200ps width*3: for 200mA input current*4: for 100mA input current

8

Cosmic testCosmic ray test@Tsinghua August, 2011

Efficiency > 95% @ 96kV/cm (6.0kV)Time resolution: ~ 52ps

PMT3

PMT4

PMT0

PMT2

PMT1

MRPC

Cosmic Ray Muon

5.8 6.0 6.2 6.4 6.6 6.860

65

70

75

80

85

90

95

100

Effi

cien

cy (

%)

HV (kV)

9

2.Beam test @ Hall A

Shield

High Energy e-

Top View

PMT1

PMT2

PMT3

PMT4

PMT0Target

Target Test setup The diagram of DAQ system

10

5.Results & Comparison: CalibrationExample: r175Operated on May 13th

High Voltage: ±6800VCondition: 10m from

target, shielded

PMT before calibration MRPC before calibration4 calibrations

Charge Cut： 2 σ

Position Cut： 2 σ

11

Calibration of PMT Calibration of MRPC

5.Results & Comparison: CalibrationExample: r175Operated on May 13th

High Voltage: ±6800VCondition: 10m from

target, shielded

Time resolution: 76ps

σ-PMT = 2.937(102.8ps)

σ-MRPC = 3.646(127.6ps)

σ-MRPC = 2.16(75.6ps)

In this test, T0 is about 100ps, the time resolution is deteriorated.

12

5.Results & Comparison: HV Scan

Time Resolution: ~75ps

Efficiency: >95%

13

5.Results & Comparison: Rate ScanVoltage: 6800V

Flux:11kHz/cm²

Efficiency:~95%Time Resolution: 78ps

Flux:16kHz/cm²

Efficiency:~95%Time Resolution: 82ps

14

5.Results & Comparison: Flux vs. TimeRun188, 6800V (5m to target, shielded)

Run193, 6800V (5m to target, not shielded)

2.5kHz/cm²

6kHz/cm²

12kHz/cm²

14-15kHz/cm²

16-18kHz/cm² • During a run, flux is not on a stable level, which from less than 3kHz/cm² to 16kHz/cm².

• We can observe the performance by selecting data from different flux.

15

Charge spectrum at different rate

5.Results & Comparison : Charge Distribution

Base Line

Signal

• Significant reduction of charge distribution can be seen as the background rate increases.

• The reduction of electrical field is caused mainly by both background irradiation and electron beams.

• Rate capability of the counter is higher than 15kHz/cm².

16

5.Results & Comparison : Beam Test

psRF 2.39

psRFTOFRPC 8.3722

psRPC 4.54

Beam Test@HZDR June, 2012

5.Results & Comparison : Beam Test

17

Time Resolution < 40ps

Beam Test@HZDR June, 2012

HV scan Rate scan

18

6.Conclusions

• Performance of MRPC is measured. The time resolution can reach 70-80ps and the efficiency is higher than 95%. The flux is up to 16kHz/cm².

• The MRPC module is placed within 10m to the Target for 2 months, without significant performance deterioration. This means that the module can withstand long time irradiation.

• The Irradiation is uniformed. During Test, the current is large even when the rate is not very high, which means the photon or neutron background irradiation is very strong.

19

End

Thank you!